Apartment dwellers may be stretched thin in New York and other expensive markets, but they still find money to order food

At least once per day—sometimes twice—Scott Fitzgerald orders in for his meals. Mr. Fitzgerald, a liquor specialist for a rum company, pays $2,750 per month for a two-bedroom apartment in Manhattan but is happy to dish out a few more dollars for curry dishes rather than cook in his cramped kitchenette.

It turns out, cities with the highest rental prices are also responsible for generating some of the most delivery orders in the...